Wheel bearings typically fail from water and dirt contamination. The All Balls Front Wheel Bearing Kit was developed in partnership with KML Bearing and is designed for the difficult operating environment of the powersport industry.
Kit contains 2 ball bearings and 2 seals required to re-fit a wheel.
Premium EMQ quality, high-speed bearing featuring low drag, double-lip rubber seals which provide superior exclusion of water, dirt and improved grease retention.
Type TC Nitrile Elastomer wheel seals are specifically designed to keep out water and dirt.
Rubber coated outside diameter creates an optimum seal at hub.
Steel garter spring guarantees constant pressure on the axle shaft over the life of the seal.
Just descent bearings to replace OEM bearings at a better than OEM price, never had a problem using this brand. The bike is used for motocross, for people wondering if they hold up to abuse from motocross or if they hold up for people who just put around the woods or play ride.
The 2003 Grizzly 660 does not actually have separate wheel bearing seals. Once you pull it apart you can verify there are no seals in there. Also you can take a look at the OEM parts fiche to verify there aren't any seals there here: http://www.motosport.com/utility/oem-parts/YAMAHA/2003/GRIZZLY-660-4X4/REAR-WHEEL